The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Communication devices include cellular devices, Bluetooth® (BT) devices, global positioning system (GPS) devices, and network devices. The network devices may comply with various standards such as those set forth by the Institute of Electrical and Electronics Engineers (IEEE), the third Generation Partnership Project (3GPP), and other standards organizations. The communication devices typically transmit and receive radio frequency (RF) signals via RF transceivers. The RF transceivers may be occasionally integrated into integrated circuits (ICs) used in the devices.
Referring now to FIG. 1, a communication device 10 comprises transceivers 12-1, 12-2, . . . , and 12-N (collectively transceivers 12), where N is an integer greater than 1. The transceivers 12 may comply with different communication standards. For example, the transceiver 12-1 may comply with the BT standard, the transceiver 12-2 may comply with the 3GPP standard, and so on. Occasionally, the communication device 10 may communicate via multiple frequency bands. Accordingly, some of the transceivers 12 may be multi-band transceivers.
Referring now to FIG. 2A, an RF transceiver 100 comprises a transmitter 102 that transmits RF signals and a receiver 104 that receives RF signals via an antenna 105. The transmitter 102 may be a super-heterodyne transmitter, a direct conversion transmitter, or other suitable transmitter. The receiver 104 may be a super-heterodyne receiver, a direct conversion receiver, or other suitable receiver.
Although a single antenna is shown, the RF transceiver 100 may transmit and receive the RF signals via a plurality of antennas. For example, the plurality of antennas may be arranged in a multiple-input multiple-output (MIMO) configuration.
Referring now to FIG. 2B, the receiver 104 typically includes an RF front-end module 106 and an RF downconverter module 108. The RF front-end module 106 typically includes a low-noise amplifier (LNA) 110 and a filter 112. The LNA 110 amplifies the RF signals received via the antenna 105. The filter 112 filters the output of the LNA 110.
The RF downconverter module 108 typically includes an LNA 114 and a downconversion mixer 116. The LNA 114 amplifies the output of the filter 112. The downconversion mixer 116 may downconvert RF signals to baseband signals using mixers 118 and 120, which are arranged in a quadrature configuration. An oscillator 122 and a 90-degree phase shifter 124 generate clock signals that clock the mixers 118 and 120, respectively. The mixers 118 and 120 generate in-phase (I) and quadrature (Q) outputs, respectively, which are input to baseband processing circuits for further processing.
Thus, transceivers typically include a plurality of LNAs. Further, multi-band transceivers typically include a plurality of LNAs per band.